The trickiest part of looking after any kind of borderline hardy or exotic plant is knowing how and when to protect it when it gets cold. You have to decide what can be left in the ground without being harmed, what can be left in but needs protection, and what should be lifted and brought under cover.

The lines get blurred by where you live in Britain, the local microclimate of your garden, how wet your soil is in winter and how hard the cold hits in any given winter. Hardiness is not an exact science; young plants are less hardy than mature ones, as are plants in shade and wet clay soils; potted plants are less hardy than those in the ground, while variegated plants are less hardy than those with a full quota of chlorophyll in the leaves.

Decision, decisions

Hardy, leave in situ Established hardy evergreens with upright branches, eg Irish yew and bay laurel, can splay or snap under heavy snow. Prevent this by tying a girdle of soft rope loosely around the branches and brush off snow regularly. Small hardy evergreens are prone to leaf scorch if the ground freezes and moisture is locked up, so mulch now. Avoid feeding or pruning.

Hardy to -8C, but protect Ceanothus, hebe, Phormium tenax, cistus, rosemary and variegated evergreens are pretty tough, but if it’s very cold in their first year a fleece cover will protect their leaves from scorching cold winds and frost. In exposed spots I use temporary windbreaks made from willow roll.

Tie up leaves of cordyline and palms to prevent wet entering the growing point and freezing. Bubblewrap or hessian-wrap pots of camellia, magnolia, rhodendrons and raise off ground to prevent roots freezing.

Tender, leave in situ Hardy banana (Musa basjoo), Echium pininana, Tetrapanax and restios should be wrapped with bracken, hessian or fleece, left on until early March. With tree ferns (Dicksonia) use fleece or bracken to insulate the growing point.

Lift or mulch Tender bulbs and rhizomes, such as aroids, canna and ginger lilies, should be lifted and brought into a frost-free place. They’re not as tough as dahlias, gladioli and tigridia, which can survive in ordinary winters and non-wet soils under a 4in layer of mulch. Do lift dahlias in cold gardens. Banana (Ensete) should be lifted and kept in a frost-free place (see right).

Resow every spring Though some may self-seed, short-lived perennials, eg Verbena bonariensis and annual climbers, are usually sown each spring. Don’t cut back verbena now, it’s more likely to survive if left with top growth on. The same goes for lavatera, buddleia and silver-leaved herbs, such as artemisia, lavender and sage.

Take cuttings Borderline tender plants such as salvias and penstemons might come through a mild winter but it is safer to take cuttings in autumn. These should be grown in a greenhouse in winter and planted out after the frosts finish.